This invention relates to a silver halide photographic material and, more particularly, it is concerned with a color photographic material for printing.
In a color photographic material for printing, red-sensitive, green-sensitive and blue-sensitive emulsion layers receive information from a negative film through an exposure mean according to three color separation as is well-known and color reproduction is effected by color reaction of cyan, magenta and yellow couplers contained in the respective emulsion layer with oxidized color developing agent.
Of these emulsion layers, strength of color sensitization, spectral distribution, sensitized terminal should be reviewed in a red-sensitive emulsion layer. Dyes for spectral sensitization of a red-sensitive emulsion have the important functions of spectral sensitization effect, spectral sensitization wave length and development of fogging and so on and studies have been made on such dyes as cyanine, merocyanine, complex merocyanine dyes. In particular, a dicarbocyanine dye having a cyclohexene ring shows superior functions as mentioned above and practical technique of said dicarbocyanine dye is disclosed, for example, in Japanese Patent Pubication No. 10473/1971, Japanese Patent Laid-open Application Nos. 5035/1975, 151026/1977, 23520/1979 and 7629/1983 and others. However, said dicarbocyanine dye has presented the two big problems. Namely, the one is storage property with time after preparation of a silver halide photographic material up to its use and a great desensitization has been realized with lapse of time. The prior art as recited above has attempted to make an improvement therein, but satisfactory results could not be obtained yet; while the other is infrared sensor fogging or sensitive fogging which has been brought about from an infrared ray-sensitive sensor recently and frequently applied during production steps or automated steps such as a printer for a photographic material, a processing apparatus and the like. Emission wave length from said infrared ray-sensitive sensor may vary depending upon the the emission source applied, but representative infrared ray emission diode of a Ga-As epitaxial type provides 900 to 950 nm, the same type using Si does approximately 1140 nm and the same type using Ge does approximately 1880 nm. Especially, dicarbocyanine dye is much more apt to undergo said infrared sensor fogging and, as countermeasures, various studies have been made on a filter dye, an antifoggant and a layer construction in a photographic material, with unsatisfactory results.
Apart from the aforesaid problems, there has been also presented another problem with regard to a hardening agent.
As the binder for a photographic material, there has been mainly utilized a gelatin and a hardening agent has been also used together with said binder. Characteristics for said hardening agent are a rapid hardening effect, no adverse influence upon a silver halide such as fogging and others, no labour sanitary and environmetal polution problems, water-solubility and so on, with easy synthesis and inexpensive production cost. In view of the above, studies have been made on hardening agents of vinylsulfone, ethyleneimine, epoxy, N-methylol and cyanuricchloride types and a cyanuricchloride type hardening agent shows superior properties meeting almost all of the aforesaid characteristics, as disclosed in U.S. Pat. Nos. 3,325,287 and 4,076,538 and Japanese Patent Laid-open Application Nos. 19220/1973, 60612/1977, 128130/1977, 130326/1977, 1043/1981 and 40244/1982. However, it has been that the cyanuricchloride type hardening agent has a great disadvantages; namely, storage property with time is poor in a photographic material using said hardening agent to produce a high desensitization with time and an even less effect could be accomplished by the use of a desensitization retarder or a desensitization retarder may be apt to induce fogging. Moreover, storage property with time would become remarkably poor when used together with said dicarbocyanine dye having a cyclohexene ring.
With particular reference to a color photographic material for printing, if a higher sensitivity is given in said color photographic material, it is advantageous in workability for printing to reduce a time for printing, and a small difference in sensitivity with lapse of time or among lots would be desirable for a printing yield.
Under these circumstances, chemical or spectral sensitization methods have been studied on a silver halide emulsion, while the subject silver halide has also been studied so that a silver halide having a high silver chloride content may be the subject to be highly sensitized by spectral sensitization. However, the silver halide with a high silver chloride content would be readily subjected to fogging, particularly, for instance, in a high temperature rapid processing or upon storage with time, which leads to inferior image quality in a print.
On the other hand, one of the important properties of a photographic material for printing is sharpness, which may have influence upon an image quality of a print, and then various studies have been made for improvement on an antiirradiation dye, a layer construction, a base and the like. Another important property is color reproductivity and studies have also been made on a spectral sensitizing dye or filter dye. Therefore, characteristics of the antiirradiation or filter dye should be important as they may influence upon both properties as noted above; more illustratively, said characteristics are an excellent spectral absorption property, an excellent elution property in developing process and no adverse influence upon a silver halide such as reduced sensitivity or induced fogging.
As the dye meeting almost all of the above requirements for characteristics, there may be mentioned, for example, oxonol, azo and anthraquinone dyes and, inter alia, those anthraquinone dyes are superior in a prominent spectral absorption property, as disclosed in U.S. Pat. No. 2,865,752 and Japanese Patent Laid-open Application No. 33825/1973. However, the anthraquinone dye may readily induce fogging to a silver halide emulsion, which is remarkable in the silver halide emulsion with a high silver chloride content. If an antifoggant or a stabilizer is added for avoiding, a great desensitization would be induced.
Moreover, a hardening agent has a property to reduce an elution property of the antiirradiation or filter dye in developing process, which leads to inferior whiteness of a print.
This invention has been completed in view of the present circumstances as discussed hereinabove. The objects of this invention are to provide a photographic material which shows a lower infrared sensor fogging, a superior sharpness or color reproductivity and a superior whiteness, to provide a photographic material which exerts a good storage property with time or a less change in sensitivity after storage and also to provide a photographic material having a higher sensitivity.